1. Field of the Invention
The present invention relates to a magnetic material used primarily as a core in a coil, inductor, etc., as well as a coil component using such magnetic material.
2. Description of the Related Art
Coil components such as inductors, choke coils and transformers (so-called inductance components) have a magnetic material and a coil formed inside or on the surface of the magnetic material. For the magnetic material, Ni—Cu—Zn ferrite or other type of ferrite is generally used.
There has been a need for these coil components of larger current capacity (higher rated current) in recent years, and switching the magnetic material from ferrite as traditionally used, to Fe—Cr—Si alloy, is being studied in order to meet such demand (refer to Patent Literature 1). Fe—Cr—Si alloy and Fe—Al—Si alloy have a higher saturated magnetic flux density than ferrite. On the other hand, their volume resistivity is much lower than that of ferrite.
Patent Literature 1 (Japanese Patent Laid-open No. 2007-027354) discloses a method of manufacturing the magnetic material part of a laminated coil component, which is to form magnetic layers using a magnetic paste containing Fe—Cr—Si alloy grains and glass component, laminate the magnetic layers with conductive patterns and sinter the laminate in a nitrogen ambience (reducing ambience), and then impregnate the sintered laminate with thermosetting resin.
Patent Literature 2 (Japanese Patent Laid-open No. 2001-11563) discloses a method of manufacturing complex magnetic material relating to a Fe—Al—Si pressed powder magnetic core used for choke coil, etc., where such manufacturing method involves pressure-compacting a mixture of alloy powder whose primary components are iron, aluminum and silicon on one hand, and binder on the other, and then heat-treating the pressure-compacted product in an oxidizing ambience.
Patent Literature 3 (Japanese Patent Laid-open No. 2002-305108) discloses a complex magnetic material that contains metal magnetic powder and thermosetting resin, where the metal magnetic powder has a specified packing factor and a specified value or higher of electrical resistivity.